Movements in war, whether offensive or de fensive, must always be based on calculation of time and distance. In an offensive war the operations are vaster, the conditions more vari able and the elements of the calculation more uncertain. In a military point of view, the offensive has its good and its bad side. Strate gically an invasion leads to deep lines of opera tion, which are always dangerous in a hostile country. All the obstacles in the enemy's country, the mountains, rivers, defiles and forts, are favorable for defense; while the inhabitants and authorities of the country, so far from being the instruments of the invading army, are generally hostile. However, if success be obtained, the enemy is struck in a vital point; he is deprived of his resources and compelled to seek a speedy termination of the contest. For a single operation, which we call taking the initiative, the offensive is almost always ad vantageous, particularly in strategy. Indeed, if the art of war consists in throwing the masses upon the decisive points, to do this it will be necessary to take the initiative. • The attacking party knows what he is doing and what he desires to do; he leads his masses to the point where he desires to strike. Tactically, the offensive also possesses advantages, but they are less positive since, the operations being upon a limited field, the party taking the initiative cannot hide them from the enemy, who may detect his designs, and by the aid of good re serves cause them to fail. Whatever advan tages may be expected either politically or strategically from the offensive, it may not be possible to maintain it exclusively throughout the war; for a campaign offensive in the be ginning may become defensive before it ends. The offensive confers, at the outset, the power of concentrating on the flank or centre of the enemy's line of defense, and so turning or breaking it. The defender must either oppose the enemy with an inferior force at first, or abandon territory in order to assemble his forces at some point further back. On the other hand, offensive war demands great re sources, and success itself, if not absolute and decisive, entails fresh difficulties on the invader. And when he has penetrated very far within the defender's territory, the situations of the antagonists differ greatly, inasmuch as the army on the offensive is bound to its base, be that base wide or narrow, while the defensive forces may base themselves on any portion of the territory which will supply them and which their front protects. It is evident that when one belligerent power feels secure behind an unassailable frontier, and holds many issues into the enemy's territory, either by command of the sea or otherwise, it can assemble its forces unknown to its antagonists upon some point selected by itself, from whence to make an eruption into the theatre of war. And if the belligerents be divided only by a frontier line—a river such as the Rhine, or a mountain range such as the Alps—the army that passes it will nearly always find itself immensely supericir to the forces that can immediately interpose.
Battles have been stated by some writers to be the chief and deciding features of war. This assertion is not strictly true, as armies have been destroyed. by strategic operations without the occurrence of pitched battles, by a succes sion of inconsiderable affairs. It is also true that a complete and decided victory may give rise to results of the same character when there have been no grand strategic combina tions. The results of a battle generally depend upon a union of causes which are not always within the scope of the. military art; the nature of the order of battle adopted, the great or less wisdom displayed in the plan of the battle, as well as the manner of carrying out its de tails, the more or less loyal and enlightened co operation of the officers subordinate to the com mander-in-chief, the cause of the contest, the proportions and quality of the troops, their greater or less enthusiasm, superiority on one side or the other in artillery or cavalry, and the manner of handling these arms; but it is the morale of armies, as well as of nations, more than anything else, which makes victories and their results decisive. When the march of an army has been so conducted, that, when it meets the enemy on the field of battle, it has a decided advantage over him, the battle which follows will usually be more decisive than in the contrary case. A single battle well fought un der the foregoing condition has frequently been decisive of the whole campaign, and even of the war. The battle of Jena gave Napoleon advantages, which vigorously followed up in the manner so peculiar to him, soon placed the kingdom of Prussia at his feet, and left him free to turn his attention to the Russians.
Tactical and strategical consideration both enter into the problem of determining the point of attack; the consideration which will govern in any particular case will depend upon the re sults which are expected to follow the defeat of the enemy, or the risks to be run in attain ing these results. The tactical considerations relate to the advantages which can be gained on the field of battle; and the strategical to the consequences of victory. The strategical conditions are more important than the tactical, unless the difficulties of the ground are too great, and the results expected to follow do not justify the risks to be taken. Let the army P in Fig. 1, find the enemy in the position A B, with one flank resting on a hill and the other on a river, with an impossible marsh in front. The point A is both the strategical and tactical point of attack; for its capture would command the field of battle, force the enemy from his line of retreat, x y, and throw him back on the impassable obstacle opposite the left flank, A C; with the right reinforced it would be a better position for the assailed to take, as in this case an attack at A would compel the assailant to fight with an obstacle at his back, and an attack at C would give the assailed the full benefit of the height. The position A C is also objectionable, as it presents a salient D, always a weak point in a line, because it renders both faces liable to be enfiladed. Suppose an army, acting on the defensive, to have the posi tion X Y, Fig. 2; its right uncovered, and its left resting on an impassable obstacle. The strategical point of attack is Y; for, if the left is forced back, the line of retreat A B is ex posed. But the selection of Y as the point of attack forces the assailant to fight with his back to the obstacle Z, which would be very dangerous unless greatly superior to the enemy. Rather X select as the point of attack, and depend upon vigorous fighting and pursuit for great results. Combined attacks, like combined marches, cannot be relied upon for success. They should only be undertaken when the natural features of the country are such that the enemy can be easily checked if he attempts to make a counter-attack, and when the prelimi nary movements of the troops are concealed from his view. When the features of the coun try are such that the detachments can, by tak ing up naturally strong positions, hold the enemy in check, the main body can operate with safety against the flank; for, in case of repulse, its main line of retreat would not be com promised. Much depends upon the character of the opposing general; if he be alert and al ways ready to act promptly and vigorously, any extended movements would be dangerous, al though it might under other circumstances be successfully carried out. Movements may be made with troops that are superior in numbers or in discipline, which would be very rash when the opposing forces are nearly equal, or the commanders of the same capacity. A careful reconnaissance is important in both tactical and strategical operations. A general reconnais sance has for its object the obtaining of de tailed and accurate information of countries and their armies that will be of assistance in case of war. It comprises within its scope our own as well as other countries, for the data obtained may be useful in prosecuting military studies, and as an aid to a general in drawing up his plan of operations, which includes the movements of troops necessary for concentrafion as well as their employment after this has been accomplished and they are ready to meet the enemy. Tables of statistics, giving population, manufactures, industries and information con cerning the roads, railroads, canals, rivers, im portant improvements, etc.; geographies, general and military; reports of various kinds, etc., win all be found of great assistance in compiling the required information. But, however com plete and exhaustive these sources of informa tion may be, officers of the army should fre quently be sent to different countries to examine and report not only upon their military systems, but upon any subject which may become im portant in a military point of view. This method not only serves to retain possession of arms, as by its assistance, woods or other sus picious places, within range, could be effec tively examined or cleared of the enemy's pres ence, without the necessity of a close approach. Guns can also cause the withdrawal of parties of the enemy from small defensive positions by acting on their flank.